JP2001197746A - Power converter controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct highly precise control and operation with a power factor 1 at low switching frequency. SOLUTION: This power converter controller is provided with a means 11 for delivering a command of DC current of the power converter, a DC current detecting means 10 for obtaining the detected value of the DC current through a DC load, a DC current control means 13 for obtaining the control amount of the DC current based on the deviation of the detected value of the DC current from the command value thereof, a synchronization detecting means 16 for obtaining a synchronizing signal from the AC voltage of an AC power supply, an output current command vector generating means 21 for obtaining a current command vector of the AC current of the power converter, an output current vector generating means 23 for delivering all the current vectors of the AC current which can be generated by the power converter, an output current vector selecting means 22 for selecting a current vector based on the current commanding vector, a unit current vector distributing means 24 for distributing the selected current vector into (n) unit current vectors according to converters whose quantity is (n), and a means 25 for controlling the energizing conditions of a self-arc-extinguishing semiconductor element based on the unit current vector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a power converter constructed using a self-extinguishing semiconductor device, and more particularly to a reduction in DC current ripple and AC current harmonics at a low switching frequency. The present invention relates to a control device for a power conversion device capable of achieving the following.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a configuration example of a control device of a conventional power converter of this kind.

FIG. 8 shows an example of an electromagnet power supply for an accelerator used in medical and physics research. The electromagnet power supply needs to excite the electromagnet coil with high accuracy in order to generate a high energy proton beam. For this reason, the specification of the power supply is such that the normalized value (ΔIr / Io) of the current ripple ΔIr is 10 ⁻⁴ to 1 with respect to the rated DC current Io.
0 ^-6 order, normalized value of the follow-up property ΔIf (ΔIf / Io)
Requires high precision control on the order of 10 ^-3 to 10 ^-4 .

[0004] In FIG. 8, a power converter includes a power factor improving filter 2 connected to an AC power supply 1 and n units (n: 2).
The above is an integer, and four are shown in the figure).
And four converters 4.

[0005] The power factor improving filter 2 is mainly composed of a phase-advancing capacitor, and suppresses the delay reactive power generated by the converter 4 to improve the power factor of the AC power.

[0006] The phase shift transformer 3 has the same voltage magnitude,
And each (60 degrees / n) phase difference ((60 degrees / 4) in the figure)
= 15 degrees) with four phase-shifting transformers 3a to 3d.

The four phase-shifting transformers 3a to 3d are connected in parallel to an AC power supply 1 by connecting their primary terminals in common, and their secondary terminals are connected to the AC terminals of the four converters 4a to 4b. Are connected on a one-to-one basis to form a general 24-phase connection type circuit.

Each of the four converters 4a to 4d is composed of six arms of semiconductor elements 5a to 5f connected in a three-phase bridge. Here, a thyristor is used as an example of the semiconductor elements.

The passive (passive) filter 6 includes a converter 4
To reduce the DC output ripple of the reactor 6
and a secondary low-pass filter composed of a and a capacitor 6b. Further, in order to suppress the resonance between the reactor 6a and the capacitor 6b, a resistance load 6c is connected in series with the capacitor 6b.

The active (active) filter 7 further reduces the DC output ripple after passing through the passive filter 6, and is constituted by a self-extinguishing type semiconductor element such as an IGBT capable of high-speed switching. In the small current region of the present invention, compensation of DC current ripple and followability is performed.

The DC load 8 comprises an electromagnet coil 8a for beam acceleration and a coil internal resistance 8b.

The DC voltage detector 9 detects a voltage value of the DC load 8.

The DC current detector 10 detects a value of a current flowing through the DC load 8.

Next, the configuration and operation of the control device will be described with reference to FIGS.

In FIG. 8, a pattern generation circuit 11
A DC current pattern for exciting the electromagnet coil 8a of the DC load 8 is generated.

The output of the pattern generation circuit 11 becomes a DC current command value Id ^* , and the difference between the output and the DC current value Id obtained by the DC current detector 10 is obtained, thereby obtaining a DC current deviation ΔI ^* .
(ΔI = Id ^* Id) is obtained.

The aforementioned DC current ripple / followability is defined by this DC current deviation ΔI. That is, as shown in FIG. 9, the DC current pattern (DC current command value Id ^* )
The current waveform of one pattern is divided into four parts (P1 flat bottom, P2 acceleration, P3 flat top, P4 deceleration), and this pattern is repeated.

When the DC current rating value (flat top current value) is Io, the DC current ripple is obtained by normalizing the current ripple ΔIr included in the DC current deviation ΔI of the flat portion (P1 flat bottom, P3 flat top). It is represented by the value (ΔIr / D0).

Further, the followability is determined by the normalized value (ΔI) of the DC current deviation ΔIf of the ramp portion (P2 acceleration, P4 deceleration).
f / Io).

On the other hand, the learning controller 12 creates a pattern correction value from the DC current deviation ΔI by utilizing that the DC current command value Id ^* is a repetitive pattern. And
By adding a pattern correction value to the output of the pattern generation circuit 11 and repeating the pattern correction for a long time, the ripple and followability of the DC current is improved.

The DC current controller (ACR) 13 obtains a DC current control amount from the DC current deviation ΔI.

A DC voltage controller (AVR) 14 adds a DC current control amount to a difference between the DC voltage command value Vd ^* and the DC voltage value Vd obtained by the DC voltage detector 10 to obtain a DC voltage. Is obtained. The control amount of the DC voltage is synchronized with the output signal of the synchronization detection circuit 16 via the phase control circuit 15 and is distributed as a phase control angle signal of each of the thyristors 5a to 5f of the four converters 4a to 4d. .

When the pattern operation of the DC current is performed, the AC output of the converter 4 controls the phase of the power and generates reactive power as shown in FIG. A power factor improving filter 2 is used.

The 24-phase connection composed of four converters 4a to 4d and four phase shift transformers 3a to 3d shown in FIG. 8 reduces the amplitude of the DC output ripple and increases the ripple frequency. Although it is common as a circuit system for
Since the higher harmonic component appears in the DC output ripple, the higher harmonic component is reduced by the passive filter (second-order low-pass filter) 6.

As described above, the current ripple is 10 ^-4 to 1
Since high-precision control of the order of 0 ⁻⁶ and tracking performance of 10 ⁻³ to 10 ⁻⁴ is required, the learning controller 12 and the passive filter are controlled by using the active filter 7 in a small current region near the current command value. 6, the delay of the low frequency component is corrected, the resonance component is suppressed, and the higher harmonics are further suppressed.

[0026]

However, in the conventional control device of the power conversion device as described above, since the learning control by the repetitive operation is required, a long initial setting time is required until the actual operation.

Further, since the operating conditions need to be unified at the time of learning control adjustment, it is easily affected by disturbance such as power supply fluctuation.

On the other hand, when a self-extinguishing element such as an IGBT is used in place of a thyristor constituting a bridge in the converter, instantaneous control is possible. In this case, the switching frequency of the element is limited, and the ability to improve the DC output ripple / followability may be poor.

A conventional thyristor-based converter suitable for high-power use outputs reactive power in power control such as DC current pattern operation in order to perform phase control. Since this reactive power is a factor that hinders stabilization of the AC power supply 1, the power factor improving filter 2 is required.

An object of the present invention is to provide a control device of a power converter capable of realizing high-precision control at a low switching frequency and also performing a power factor 1 operation on the AC side. It is in.

[0031]

According to a first aspect of the present invention, a self-extinguishing type semiconductor device is connected in a bridge to convert AC power into DC power. (N: an integer of 2 or more) and n phase-shift transformers having the same voltage magnitude and each having a phase difference of (60 degrees / n), and n phase-shift transformers The primary terminals of the transformers are connected in common and connected in parallel to an AC power supply, and the secondary terminals are connected to the AC terminals of n converters in a one-to-one correspondence, and n units (= m × l) Control of a power converter in which m (m: an integer of 1 or more) series-connected converters are connected in parallel to one set (m is an integer of 1 or more) of DC terminals of the converters A means for providing a DC current command value of the power converter, and a detection value of a DC current flowing through a DC load. DC current detection means, DC current control means for obtaining a control amount of DC current based on a deviation between a command value of DC current and a detection value of DC current, and synchronization detection means for obtaining a synchronization signal from an AC voltage of an AC power supply And an output current command vector generating means for obtaining a current command vector of the AC current of the power converter based on the control amount of the DC current and the synchronization signal of the AC voltage, and all of the AC currents that the power converter can generate. Output current vector generating means for providing a current vector, output current vector selecting means for selecting a current vector based on a current command vector, and a current vector selected by the output current vector selecting means according to n converters. Unit current vector distribution means for distributing the current to n unit current vectors, and controlling the energization state of the self-extinguishing type semiconductor element based on the unit current vector. Means.

Therefore, in the control device of the power converter according to the first aspect of the present invention, by applying vector control to the main circuit configuration multiplexed by the phase shift transformer, a unit that can be output by one converter is provided. The current vector can have a phase difference between the multiplexed converters. As a result, since the same unit current vector does not exist between the multiplexed converters, the number of output current vectors (composite vector of the multiplexed unit current vectors) can be increased to realize high-precision control. it can. In the vector control, the output current can be controlled by a combination of unit current vectors that can be generated by the unit converter. Therefore, the switching frequency is reduced without unnecessary on / off control of the self-extinguishing element. be able to. As described above, it is possible to achieve both low switching frequency and high precision control. In addition, since each converter forms a bridge with a self-extinguishing type element, energization control can be performed instantaneously by ON / OFF control of the self-extinguishing type element. That is, according to the DC current command value, the output current vector synchronized with the AC voltage is instantaneously selected and distributed to the unit current vector of each converter to perform ON / OFF control of the self-extinguishing element. , Instantaneous value control and power factor 1 operation become possible.

Further, in the invention corresponding to claim 2, n converters (n: an integer equal to or greater than 2) for converting AC power into DC power by connecting a self-extinguishing type semiconductor element in a bridge, And n phase-shifting transformers having the same voltage magnitude and each having a phase difference of (60 degrees / n). In parallel with the power supply, the secondary terminals are connected one-to-one to the AC terminals of the n converters, respectively, and m (m) of the DC terminals of the n converters (= m × l) are connected. : 1 (integer of 1 or more) The series-connected converters are connected in parallel to a DC load by 1 set (1: an integer of 1 or more), the reactor is connected in series to the DC load, and the capacitor is connected in parallel to the DC load. In a control device for a power conversion device having a DC filter, Means for providing a command value of a DC current detecting means for obtaining a detection value of the direct current flowing in the DC load,
DC current control means for obtaining a control amount of DC current based on a deviation between a command value of DC current and a detection value of DC current; synchronization detection means for obtaining a synchronization signal from an AC voltage of an AC power supply; Output current command vector generating means for obtaining a current command vector of the AC current of the power converter based on the amount and the synchronizing signal of the AC voltage, and an output current providing all the current vectors of the AC current that the power converter can generate Vector generating means, output current vector selecting means for selecting a current vector based on the current command vector, and the current vector selected by the output current vector selecting means as n
A unit current vector distributing means for distributing the current to n unit current vectors according to the converters, and a means for controlling the energization state of the self-extinguishing semiconductor device based on the unit current vector.

Therefore, in the control device for a power conversion device according to the present invention corresponding to claim 2, in the control device for a power conversion device according to the invention according to claim 1, the reactor is connected in series to the DC load, and the capacitor is connected. By providing the DC filter connected in parallel to the DC load, the peak voltage (switching frequency component) at the time of current interruption generated by the ON / OFF control of the self-extinguishing element can be suppressed by the DC filter. The current ripple can be reduced. Further, since a detection value of the direct current in which the influence of the switching frequency component is reduced can be obtained, high-accuracy control can be realized.

According to a third aspect of the present invention, in the control device for a power converter according to the first or second aspect of the present invention, the output current vector generating means includes all current vector values of the alternating current. And a storage means for storing the current vector value obtained by the calculation means.

Therefore, in the control device of the power converter according to the third aspect of the present invention, all the current vector values of the alternating current that can be generated by the power converter are 7 ⁿ types,
If the calculation is performed for each control cycle, the calculation load (calculation time) is applied to the microcomputer or the DSP (digital signal processor). Therefore, the calculation is completed in the initial state and the calculation result is stored in the memory, thereby reducing the calculation time. High precision control can be realized by shortening to about 1/7 ⁿ .

According to a fourth aspect of the present invention, in the control device for a power converter according to the first or second aspect, the output current vector selecting means includes a current vector corresponding to the current command vector. According to the storage means for storing the selected value of in advance and the current command vector,
Means for retrieving the selected value of the current vector from the storage means.

Therefore, in the control device of the power conversion device according to the present invention, when selecting a current vector corresponding to the current command vector, a minimum of 2
If the selection is made by operation comparison by multiplication or the like, the operation load (operation time) is imposed on a microcomputer or a DSP (digital signal processor). Therefore, the operation time can be calculated by setting a current vector selection value according to the current command vector in advance. Can be reduced to about one sampling, and high-accuracy control can be realized.

[0039]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a circuit diagram showing a configuration example of a control device of a current source converter according to the present embodiment. The same elements as those in FIG. The description will be omitted, and only different portions will be described here.

In FIG. 1, four converters 4a to 4d
Is composed of self-extinguishing semiconductor elements 5a 'to 5f' for six arms each connected in a three-phase bridge. Here, as an example of a self-extinguishing semiconductor element, IEGT (I
njection Enhanced Gate Tr
anstor element.

Since the IEGT elements 5a 'to 5f' have parasitic diodes connected in anti-parallel inside the elements, FIG.
In the figure, a series diode is added for preventing reverse conduction.

That is, the current-source converter has a bridge connection of IEGT elements 5a 'to 5f', and four (n = 4) converters 4a to 4d for converting AC power to DC power.
And the magnitude of the voltage is equal, 15 degrees each (= 60 degrees / 4)
(N = 4) phase-shift transformers 3a to 3
d (3a: 0 degrees, 3b: 15 degrees, 3c: 30 degrees, 3d:
45 degrees).

The primary terminals of the four phase-shift transformers 3a to 3d are connected in common and connected in parallel to the AC power supply 1, and the secondary terminals are connected to the AC terminals of the four converters 4a to 4d. And four (= 2 × 2) DC terminals of four (= 2 × 2) converters connected in series (m = 2).
a, 4b and 4c, 4d are connected to the DC load 8 in two sets (l =
2) It is configured by connecting in parallel.

Further, converters 4a, 4b and 4c, 4
When d and the DC load 8 are connected in parallel, balancing reactors 20a to 20d are provided so that current imbalance does not occur between the two sets of converters (4a, 4b and 4c, 4d).

The power factor improving filter 2 in FIG. 8 is omitted.

On the other hand, the control device comprises a pattern generation circuit 11
, DC current controller (ACR) 13, and synchronization detection circuit 1
6, an output current command vector generation circuit 21, an output current vector selection circuit 22, and an output current vector generation circuit 2
3, a unit current vector distribution circuit 24, and a gate signal generation circuit 25.

The pattern generating circuit 11 gives a DC current command value for the current source converter.

The DC current controller 13 controls the DC current based on the deviation between the command value of the DC current from the pattern generation circuit 11 and the detected value of the DC current flowing from the DC current detector 10 to the DC load. Get the quantity.

The synchronization detection circuit 16 obtains a synchronization signal from the AC voltage of the AC power supply 1.

The output current command vector generation circuit 21 outputs the AC current of the current source converter based on the control amount of the DC current from the DC current controller 13 and the synchronization signal of the AC voltage from the synchronization detection circuit 16. Obtain the current command vector.

The output current vector generating circuit 23 gives all the current vectors of the alternating current that can be generated by the current source converter.

The output current vector selection circuit 22 selects a current vector from the output current vector generation circuit 23 based on the current command vector from the output current command vector generation circuit 21.

The unit current vector distribution circuit 24 distributes the current vector selected by the output current vector selection circuit 22 into n (n = 4) unit current vectors according to the n converters 4a to 4d. .

The gate signal generation circuit 25 generates a signal based on the unit current vector from the unit current vector distribution circuit 24.
The power supply state of the IEGT elements 5a 'to 5f' is controlled.

Next, the operation of the control device for the current-source converter of the present embodiment configured as described above will be described.
The principle of the control will be described with reference to FIGS.

In FIG. 1, the pattern generating circuit 11 generates a DC current pattern for exciting the electromagnet coil 8a of the DC load 8. The output of the pattern generation circuit 11 becomes the DC current command value Id ^* , and the DC current detector 10
By taking the difference from the DC current value Id obtained by the above, the DC current deviation ΔI is obtained.

In the DC current controller 13, the DC current deviation Δ
From I, the control amount of the direct current can be obtained.

On the other hand, in the synchronization detection circuit 16, the AC power supply 1
A synchronous signal is obtained from the AC voltage.

In the output current command vector generation circuit 21,
The control amount of the direct current is an amplitude element M, and the synchronization signal is a phase element θ.
, An output current command vector is generated.

Then, using this output current command vector, space vector control is performed thereafter.
The principle of space vector control in the case of the transformer multiplexing method will be described.

As shown in FIG. 2 (a), the converter per unit is composed of IEGT elements 5a 'to 5f'. IEGT
Depending on the conduction state of the element, as shown in FIGS. 2B and 2C, the arm is short-circuited and the zero current vector ◎ (UX, VY, WZ phase) which makes the output current zero. , “Six types” of unit current vectors (UZ phase), (VZ phase),
(VX phase), (WX phase), (WY phase),
(U-Y phase) can be output.

As shown in FIG. 3A, in the case of the transformer multiplex system (24-phase configuration), the unit current vectors of the four converters 4a to 4d are transferred to the converters connected to the converters 4a to 4d. The phase transformers 3a to 3d have a phase difference of 15 degrees,
It becomes possible to select four (6 × 4) unit current vectors.

On the other hand, as shown in FIG. 3B, a direct multiplexing method (parallel 4
In the case of multiplexing), the unit current vectors of the four converters are the same, and remain six.

Therefore, as shown in FIG. 4A, in the case of a 24-phase configuration, there are 2401 combined current vectors (output current vectors) by combining the unit current vector and the zero vector of the four converters. 2401 = 7 ⁴ ).

On the other hand, as shown in FIG. 4B, in the case of parallel 4-multiplexing, there are 61 output current vectors.

[0067]

(Equation 1)

Is obtained.

The large number of selected output current vectors means that
This indicates that the vector density is high, and the control accuracy of the combination given the current command vector can be increased.

In the control device of the present embodiment, by applying space vector control to the main circuit configuration multiplexed by the phase shift transformers 3a to 3d, the same control as in the case without the phase shift transformer is achieved. About 40 times the number of converters (= 2401/6
The vector selection of 1) becomes possible, and high-accuracy control can be realized.

That is, in FIG. 1, the output current command vector generated by the output current command vector generation circuit 21 is converted by the output current vector selection circuit 22 into 2401 output current vectors ( An output current vector that is the same as or approximate to the output current command vector is selected from the composite vectors of the unit current vectors).

In this case, as an example of the selection method, the output current command vector (X ₀ , Y ₀ ) is compared with 2401 types of output current vectors (X _n , Y _n : n = 1 to 2401). , the output current vector Bokuruchi the deviation E is minimum _{(X n ', Y n'} ) least squares method for selecting and the like.

(X ₀ −X _n ) ² + (Y ₀ −Y _n ) ² = E
_min → (X _n ′, Y _n ′) The output current vector obtained by the output current vector selection circuit 22 is converted by the unit current vector distribution circuit 24 into a unit corresponding to four converters which have become components of the output current vector. The current vector is distributed to the IEGT element 5a of each phase of the four converters 4a to 4d via the gate signal generation circuit 24.
'To 5f' are controlled for conduction.

In the space vector control, since the output current can be controlled by a combination of unit current vectors that can be generated by the unit converter, the ON / OFF control of the IEGT elements 5a 'to 5f' is not performed unnecessarily, and the switching is performed. The frequency can be reduced.

As described above, the control device of the current-source converter according to the present embodiment can achieve both low switching frequency and high-precision control.

The IEGT elements 5a 'to 5f' constituting the four converters 4a to 4d are provided with gate signal generation circuits, whereas the thyristor conduction control is influenced by the commutation condition of the AC power supply 1. The on / off control of 25 enables instantaneous conduction control.

Further, since the output current vector on the vector circle synchronized with the AC voltage is selected, the power factor 1 operation becomes possible.

In this embodiment, the case where the transformer has a four-stage configuration (24-phase configuration) is described. However, by increasing (multiplexing) the number of transformer stages, the density of the output current vector is reduced. In addition, the effect of the high precision control can be further improved.

(Second Embodiment) FIG. 5 is a block diagram showing a configuration example of a control device of a current source conversion device according to the present embodiment, and the same elements as those in FIG. A description thereof is omitted, and only different portions will be described here.

That is, as shown in FIG. 5, the control device of the current-source converter according to the present embodiment includes reactors 6aa to 6aa to
FIG. 1 is a configuration in which a secondary low-pass filter (hereinafter, referred to as a passive filter) 6 that is a DC filter in which 6ad is connected in series to a DC load 8 and a capacitor 6b ′ is connected in parallel to the DC load 8 is added to FIG. And

FIG. 5 shows an example in which the reactors 6aa to 6ad, which are components of the passive filter 6, and the above-described balancing reactors 20a to 20d are used as common elements.

Next, the operation of the control device of the current-source converter of the present embodiment configured as described above will be described.

The description of the operation of the same part as that of the first embodiment is omitted, and only the operation of the different part will be described here.

In FIG. 5, four converters 4a to 4d
Is connected to the IEGT of each phase through the gate signal generation circuit 24.
The conduction of the elements 5a 'to 5f' is controlled.

In this case, when the IEGT elements 5a 'to 5f' are switched, a peak voltage (also called switching surge) is generated due to interruption of the conduction current. This peak voltage is superimposed on the DC voltage and becomes a factor to increase the DC current ripple.

Therefore, even if high-precision control using a space vector is performed in the control system, a passive filter 6 is provided in the DC circuit so that the control performance is not impaired by the disturbance of the peak voltage generated on the main circuit. In addition, it is possible to mainly suppress harmonics (ripple) of the switching frequency component.

As described above, the control device for the current-source converter according to the present embodiment can obtain the same effects as those of the above-described first embodiment.
Peak voltage at the time of current interruption (switching frequency component) generated due to on / off control of elements 5a 'to 5f'
Can be suppressed by the passive filter 6, so that the DC current ripple can be reduced.

Further, since it is possible to obtain a detected value of the direct current in which the influence of the switching frequency component is reduced, it is possible to realize high precision control.

(Third Embodiment) FIG. 6 is a block diagram showing a configuration example of a main part of a control device of a current source conversion device according to the present embodiment. The same elements as those in FIG. 1 or FIG. The description is omitted by attaching the reference numerals, and only different portions will be described here.

That is, as shown in FIG. 6, the control device of the current-source converter according to the present embodiment includes an arithmetic circuit 26 in the output current vector generation circuit 23 in FIG. 1 or FIG.
And a memory circuit 27.

The arithmetic circuit 26 obtains in advance all current vector values of the alternating current.

The memory circuit 27 stores all the current vector values obtained by the arithmetic circuit 26.

Next, the operation of the control device of the current-source converter of the present embodiment configured as described above will be described.

The description of the operation of the same part as in the first or second embodiment is omitted, and only the operation of the different part will be described here.

In FIG. 6, in the arithmetic circuit 26, the first to fourth stages of the converter (converter 4) shown in FIG.
a to 4d), the vector is x
When expressed on the −y axis, it can be obtained by the following formula.

(1) First stage of converter x1 = M '* cos (60 degrees * i + 0 degrees) y1 = M' * sin (60 degrees * i + 0 degrees) x1 = y1 = 0 (i = 0) (2) Second stage of converter x2 = M '* cos (60 degrees * j-15 degrees) y2 = M' * sin (60 degrees * j-15 degrees) x2 = y2 = 0 (j = 0) (3) Converter Third stage x3 = M '* cos (60 degrees * k-30 degrees) y3 = M' * sin (60 degrees * k-30 degrees) x3 = y3 = 0 (k = 0) (4) Four stages of converter Eye x4 = M '* cos (60 degrees * 1-45 degrees) y4 = M' * sin (60 degrees * 1-45 degrees) x4 = y4 = 0 (l = 0) where i, j, k, l = 0 to 6: Number of vectors that can be taken by the unit converter (◎ zero vector + unit vector〜) In the memory circuit 27, n =
1 to 2401 are stored in advance by the following calculation formula.

X (n) = x1 + x2 + x3 + x4 y (n) = y1 + y2 + y3 + y4 n = 1 to 2401 As described above, the output current vector generation circuit 23 does not need to always perform the operation of the operation circuit 26 when the vector is generated. Vectors can be selected quickly.

As described above, the control device of the current-source converter according to the present embodiment can obtain the same effects as those of the above-described first or second embodiment. There are 7 ⁿ = 2401 types of all current vector values of the alternating current that can be generated by the shape conversion device, and if calculation is performed for each control cycle, a calculation load (calculation time) is required for a microcomputer or a DSP (digital signal processor). By performing the calculation in advance in the initial state and storing the calculation result in the memory circuit 27, the calculation time can be reduced to about 1/7 ⁿ = 1/2401 and high-precision control can be realized. It becomes possible.

(Fourth Embodiment) FIG. 7 is a block diagram showing an example of a configuration of a main part of a control device of a current source conversion device according to the present embodiment. The same elements as those in FIG. 1 or 2 are the same. The description is omitted by attaching the reference numerals, and only different portions will be described here.

That is, as shown in FIG. 7, the control device of the current-source converter according to the present embodiment includes a memory circuit 28 in the output current vector selection circuit 22 in FIG. 1 or FIG.
And an output current vector selection circuit 22 '.

The memory circuit 28 previously stores a current vector selection value corresponding to the current command vector.

The output current vector selection circuit 22 'calls the selected value of the current vector from the memory circuit 28 according to the current command vector.

Next, the operation of the control device of the current-source converter of the present embodiment configured as described above will be described.

The description of the operation of the same part as that of the first or second embodiment is omitted, and only the operation of the different part will be described here.

In FIG. 7, in the memory circuit 28, the output current vector values (x (n), y (n)) corresponding to the output (M, θ) of the output current command vector generation circuit 21 are assigned in advance to the nth Is stored.

In the output current vector selection circuit 22 ′, when the output current command vector (M, θ) is obtained, the output current vector value (x (n), y (n)) allocated in advance from the memory circuit 28 is obtained. can get.

As described above, when selecting an output current vector, it is not necessary to compare and select a plurality of output current vector values with an output current command vector value. Therefore, the output current vector can be selected at high speed.

As described above, the control device of the current-source converter according to the present embodiment can obtain the same effects as those of the above-described first or second embodiment. When selecting a current vector corresponding to a command vector by performing operation comparison by the least squares method or the like for each control cycle, the operation load (operation time) on a microcomputer or a DSP (digital signal processor) increases. By determining the current vector selection value according to the current command vector in advance, the calculation time can be reduced to about one sampling, and high-precision control can be realized.

(Other Embodiments) (a) In the embodiment described above, a 24-phase configuration (n = 4)
However, the present invention is not limited to a 24-phase configuration. For example, a case where two or more sets of a multiple connection configuration such as a 12-phase configuration or a 24-phase configuration or a multiple-configuration configuration such as a 24-phase configuration are connected in parallel is used. Also, the same effects as described above can be obtained by applying the present invention in the same manner.

(B) In the above-described embodiment, the case where one set of self-extinguishing type element is configured for one arm of the bridge circuit has been described. However, in the present invention, the self-extinguishing type element is connected in series or in parallel. The present invention is not limited to this. For example, even when a plurality of self-extinguishing elements are connected to form one arm, it is possible to obtain the same effects as described above by applying the present invention in the same manner.

(C) In the above-described embodiment, the case of the configuration using the three-phase bridge circuit has been described. However, the present invention is not limited to the three-phase bridge circuit, but may be a single-phase or higher-phase bridge circuit. In this case, the same effect can be obtained by applying the present invention in the same manner.

(D) In the above-described embodiment, with respect to claims 1 to 4 of the present invention, the case of the configuration for each claim has been described. However, the present invention is not limited to the configuration for each claim. Instead, by configuring each claim in combination,
It is possible to obtain the same effect as described above, or a synergistic effect.

[0113]

As described above, according to the control device of the power converter of the present invention, the phase shift transformer is applied by applying the space vector control to the main circuit configuration multiplexed by the phase shift transformer. Since the selectable range of the unit current vector branched by the phase difference of the output current vector is increased, the selectable range of the output current vector, which is a combination of the unit current vectors, can be increased, and the number of switching times is inadvertently increased. High-accuracy control can be realized without increasing. In addition, since the output current vector on the vector circle synchronized with the AC voltage is selected, the power factor 1 operation can be performed.

Further, when the output current vector is selected, the vector is stored in a memory in advance, and the selection range is narrowed down from all the current vectors by the phase angle, the amplitude, and the hysteresis. It is possible to realize a high-accuracy control by shortening the selection time (control operation time).

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a control device for a current-source converter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 2 is a diagram showing an example of space vector control operation in the control device of the current source conversion device according to the first embodiment.

FIG. 3 is a diagram showing an example of a unit current vector comparison between a transformer multiplexing method and a direct multiplexing method in the control device of the current source conversion device according to the first embodiment;

FIG. 4 is a diagram showing an example of a comparison between output current vectors of a transformer multiplexing method and a direct multiplexing method in the control device of the current source conversion device according to the first embodiment;

FIG. 5 shows a second control device of the current-source converter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 6 shows a third control device of the current-source converter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 7 shows a fourth embodiment of the control device of the current-source converter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 8 is a block diagram showing a configuration example of a control device of a conventional power converter.

FIG. 9 is a diagram showing an operation example of a conventional power converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... AC power supply 2 ... Power factor improvement filter 3,3a-3d ... Phase shift transformer 4,4a-4d ... Converter 5a-5f ... Thyristor 5a'-5f '... IEGT 6 ... Basic filter 6a, 6aa-6ad ... Reactor 6b ... Capacitor 6c ... Resistance load 7 ... Active filter 8 ... DC load 8a ... Electromagnetic coil 8b ... Coil internal resistance 9 ... DC voltage detector 10 ... DC current detector 11 ... Pattern generation circuit 12 ... Learning controller 13 ... DC current controller (ACR) 14 DC voltage controller (AVR) 15 Phase control circuit 16 Synchronization detection circuit 20a to 20d Balance reactor 21 Output current command vector generation circuit 22, 22 'Output current vector selection Circuit 23 ... Output current vector generation circuit 24 ... Unit current vector distribution circuit 25 ... Gate signal generation circuit 2 6. Arithmetic circuit 27, 28 ... Memory circuit.

Claims (4)

[Claims] 1. An n-unit (n: an integer equal to or greater than 2) converter for converting AC power into DC power, comprising a self-extinguishing type semiconductor element bridge-connected, and having the same voltage magnitude and (60 degrees / n) having a phase difference of 60. The primary terminals of the n phase-shift transformers are connected in common and connected in parallel to an AC power source. Secondary terminals are connected to the AC terminals of the n converters in a one-to-one correspondence, respectively, and m DCs (m is an integer of 1 or more) among the DC terminals of the n converters (= m × l) In a control device for a power conversion device in which one series (one or more integers of 1 or more) of converters connected in series are connected in parallel to a DC load, a means for giving a DC current command value of the power conversion device; DC current detection means for obtaining a detection value of a DC current flowing in a DC load, a command value of the DC current and DC current control means for obtaining a control amount of a DC current based on a deviation from a detection value of a flowing current; synchronization detection means for obtaining a synchronization signal from an AC voltage of the AC power supply; and a control amount of the DC current and the AC Output current command vector generating means for obtaining a current command vector of an AC current of the power converter based on a voltage synchronization signal; and an output current vector for providing all current vectors of the AC current that the power converter can generate. Generating means; output current vector selecting means for selecting the current vector based on the current command vector; n current vectors selected by the output current vector selecting means according to the n converters A unit current vector distributing means for distributing the unit current vector of the self-extinguishing type semiconductor element based on the unit current vector. A control device for a power conversion device, comprising: a control unit. 2. An n-unit (n: an integer of 2 or more) converter for converting an AC power into a DC power by bridging a self-extinguishing type semiconductor element, and having the same voltage magnitude and (60 degrees / n) having a phase difference of 60. The primary terminals of the n phase-shift transformers are connected in common and connected in parallel to an AC power source. Secondary terminals are connected to the AC terminals of the n converters in a one-to-one correspondence, respectively, and m DCs (m is an integer of 1 or more) among the DC terminals of the n converters (= m × l) A set of converters connected in series is connected in parallel to a DC load by 1 set (1: an integer of 1 or more), and a DC filter in which a reactor is connected in series to the DC load and a capacitor is connected in parallel to the DC load. A control device for a power converter, comprising: a DC current command for the power converter. Means for giving a value, a DC current detecting means for obtaining a detected value of a DC current flowing through the DC load, and a control amount of the DC current based on a deviation between a command value of the DC current and a detected value of the DC current. DC current control means for obtaining; a synchronization detection means for obtaining a synchronization signal from an AC voltage of the AC power supply; and a current of the AC current of the power converter based on the control amount of the DC current and the synchronization signal of the AC voltage. Output current command vector generating means for obtaining a command vector; output current vector generating means for providing all current vectors of the alternating current that can be generated by the power conversion device; and selecting the current vector based on the current command vector. Output current vector selection means; and a current vector selected by the output current vector selection means, the number of unit current vectors corresponding to the n number of converters. And a means for controlling the energization state of the self-extinguishing type semiconductor element based on the unit current vector. . 3. The control device for a power conversion device according to claim 1, wherein the output current vector generating means includes: an arithmetic means for previously obtaining all current vector values of the AC current; Storage means for storing the current vector value obtained by the means, and a control device for the power conversion device. 4. The control device for a power conversion device according to claim 1, wherein the output current vector selection unit stores in advance a current vector selection value corresponding to the current command vector. And a means for calling a selected value of the current vector from the storage means in accordance with the current command vector.